Light, slim and compactable mobile devices have gradually been favoured by consumers, along with the advancement of science and technology. To be used conveniently, a mobile device is usually equipped with a battery module, in order for the user to operate the mobile device through supplying power from the battery module under the condition that no external power supply is available.
Nowadays, for mainstream battery applications, most mobile devices such as a mobile phone, a tablet PC or a notebook computer are used lithium batteries as the power sources. Although the lithium battery has a high energy density, the lithium battery still occupies the largest portion within the mobile device, as compared with other components of the mobile device.
Thus, in consideration of product dimension, the capacity of the battery module for the lithium-based battery will be limited due to dimension, so that the mobile device can not be used over a long period of time. If the consideration is based on the usage time of the mobile device and the larger lithium battery is thus applied, the dimension of the mobile device will be difficult to reduce and such device fails to meet the consumer needs.
Among the new generation of batteries, a paper battery is capable of compensating the drawback that the volume of the mobile device is largely occupied by the lithium battery. More specifically, the paper battery is flexible, bendable and puncturable, so that the disposition thereof can be more flexible and further altered within the mobile device, thereby reducing the overall dimension of the mobile device.
However, the energy density of the paper battery is still lower than that of the mainstream lithium battery, and the paper battery can not merely be used as the primary power source of the mobile device. Additionally, there is a significant difference between the charging/discharging abilities of the paper battery and the lithium battery. If the conventional mean (i.e., connecting in parallel) is applied to connect the lithium battery and the paper battery to enhance the overall capacity of the battery module, the paper battery will be damaged, and the damages can even be caused on the mobile device.